Department of Oral Pathology, Oral Cancer Research Institute, Brain Korea 21 Project, College of Dentistry, Yonsei University, Seoul, 120-752, South Korea.
Lasers Med Sci. 2015 Feb;30(2):499-507. doi: 10.1007/s10103-013-1350-1. Epub 2013 May 23.
Photodynamic therapy (PDT) with photosensitizer is one of the promising modalities for cancer treatment. For clinical use of PDT, screening process should be preceded to enhance sensitivity to PDT. Thus, we investigated a molecular biomarker to determine the sensitivity to pheophorbide a (Pa)-PDT in immortalized human oral keratinocytes (IHOK) and oral squamous cell carcinoma (OSCC) cell lines. Two IHOK and several OSCC cell lines were used. After Pa-PDT, cell viability was reduced by more than 50%, and reactive oxygen species were generated in IHOK and OSCC cell lines. Additionally, apoptosis occurred in PDT-treated cells. IHOK(S) and IHOK(P), the two IHOK cell lines derived from the same source, showed a difference in cytotoxicity after Pa-PDT. To explain this difference in cytotoxicity, we looked at the expression of Wnt signaling-related genes in these two cell lines, for the morphology of IHOK(S) which was spindle like and elongated and distinct from IHOK(P) and the parent cell. Among the relevant genes, runt-related transcription factor 3 (RUNX3), an apoptosis-related gene, was selected as a potential marker that confers sensitivity to PDT. We found that the cytotoxicity by Pa-PDT was proportional to RUNX3 expression in OSCC cell lines. Additionally, knockdown of RUNX3 expression reduced cytotoxicity by Pa-PDT, suggesting that RUNX3 might be a biomarker to determine sensitivity to Pa-PDT. This was the first study to find a new target molecule that enhances Pa-PDT effects in IHOK and OSCC cell lines. Hence, the development of a PDT-dependent biomarker could provide a novel approach to improve the effects of PDT on oral precancerous and cancerous lesions.
光动力疗法（PDT）与光敏剂是癌症治疗的有前途的方法之一。为了临床应用 PDT，应该进行筛选过程以提高对 PDT 的敏感性。因此，我们研究了一种分子生物标志物，以确定在永生化人口腔角质形成细胞（IHOK）和口腔鳞状细胞癌细胞系中对叶啉 a（Pa）-PDT 的敏感性。使用了两种 IHOK 和几种 OSCC 细胞系。在 Pa-PDT 后，细胞活力降低了 50％以上，并且在 IHOK 和 OSCC 细胞系中产生了活性氧。此外，在 PDT 处理的细胞中发生了细胞凋亡。从同一来源衍生的两种 IHOK 细胞系 IHOK(S) 和 IHOK(P)在 Pa-PDT 后的细胞毒性方面存在差异。为了解释这种细胞毒性差异，我们研究了这两种细胞系中与 Wnt 信号相关的基因表达，因为 IHOK(S)的形态呈纺锤形和拉长形，与 IHOK(P)和母细胞不同。在相关基因中，与凋亡相关的基因 runt 相关转录因子 3（RUNX3）被选为赋予 PDT 敏感性的潜在标志物。我们发现，在 OSCC 细胞系中，Pa-PDT 的细胞毒性与 RUNX3 表达成正比。此外，RUNX3 表达的敲低降低了 Pa-PDT 的细胞毒性，表明 RUNX3 可能是确定 Pa-PDT 敏感性的生物标志物。这是第一项在 IHOK 和 OSCC 细胞系中发现新的靶分子以增强 Pa-PDT 效果的研究。因此，开发 PDT 依赖性生物标志物可以为改善 PDT 对口腔癌前病变和癌症病变的效果提供新方法。
